| 摘要 |
PURPOSE:To solve the problem of residue on a side surface, to implement a method suitable for high integration density with O-N-O (SiO2/Si3N4/SiO2) as an interlayer insulating film and to make it possible to implement high performance, by changing vertical machining into taper machining by dry etching for a floating gate. CONSTITUTION:A slant part is provided at the machining end of a first conductor (becomes a floating gate after machining) 54 by a so-called taper machining. An O-N-O insulating film 55 is deposited on the conductor. A second conductor material 56 is further formed. Thereafter, resist is applied on a part, which is a control gate, by a photoetching process. With the resist as a mask, the second conductor layer at an unnecessary part is removed by dry etching. At this time, the thickness of the O-N-O film on the side wall of the first conductor layer viewed from the upper side is thin because the machining end is inclined. Therefore, the part can be removed by vertical machining using anisotropic dry etching. As a result, the O-N-O film can be completely removed. |
